http://www.tenniscruz.com/content/view/658/1/
The slice tennis service is basically hit with a bit less forearm pronation and the ball contact is off-center as you can see in the ball picture above on the outside of the ball.
For comprehensive instruction on the tennis serve go to:
http://www.tenniscruz.com/content/view/658/1/
Wow!!! What a wonderfull pronation!! Congratulation!
armandgeist 1 month ago